Twenty-one strains of RhizobiulIl ieglllllinosarlllll val'. viceae spp (Vicia laba) 11'0111 21 sites/ofrnNorth GondaI' were isolated 11'0111 a range of pH 5.8-7.5 to induce nodulation on "Degaga"rncultivar of faba bean. Isolates were authenticated as root nodule bacteria by their ability to formrnnodules on their host up on re-inoculation, except AUFR13. All of the morphological featuresrndisplayed by all isolates were characteristics of fast growing RhizobiulIl ieglllllinosarlllll val'rnviceae, except AUFR13. Almost all of the isolates grew between 15Â°C and 35Â°C and failed torngrow at 40Â°C, except AUFR22 and AUFR28. All isolates failed to grow at 1 % NaCI, exceptrnAUFR12 and AUFR28. AUFRI8 was the only osmotolerant strain capable of growing at arnconcentration of 5%. The isolates also grew on a wide range of moderate acidity and alkalinityrnbut only 10% of the isolates grew at pH5.5. With the exception of gluconate, citrate, and tartarate,rnalmost all isolates grew on 14 out of the tested carbohydrates. The Intrinsic Antibiotic Resistancern(IAR) was found to be the best of all tested physiological characters to identify the heterogeneityrnof RhizobiulIl ieglllllinosarlllll val'. viceae, so that 95% of the tested isolate were resistrnelylhromycin and chloromphenicol, and 14%,24%,38%,38% and 43% of the isolates toleratedrnstreptomycin, ampicillin, rifampcin, kanamycin and naldixic acid at highest concentration,rnrespectively. The relative effectiveness expressed as percentage of shoot dlY mass of inoculantsrnover TN control, showed that 24%, 57%, 4.7% and 9.5% of the isolates were found to be highlyrneffective, effective, lowly effective and ineffective, respectively. The highest scores of 88-100%rneffectiveness of symbiotic nitrogen fixation were displayed by AUFRI4, AUFRI5, AUFR24,rn1-0